Band hopping generally describes the feature in which a single 802.11 Access Point (AP) serves multiple networks on different channels while utilizing a single 802.11 radio. In this regard, the AP dynamically switches from one channel to another. Before leaving one channel, the AP sets a NAV (Network Allocation Vector) on the channel to postpone any uplink transmissions during its absence. The NAV can be set, for instance, by a CTS (Clear to Send) frame. One perceived shortcoming with this approach is that that no service is available on that particular channel while the NAV is set. Consequently, service is interrupted on the current channel when an AP hops to another channel.
Furthermore, a given AP usually stays on the channel associated with its BSS (Basic Service Set) and listens for possible transmissions directed at the AP. In some cases, however, the AP may have to temporarily vacate the channel in order to perform tasks which temporarily disable its capability to serve the BSS on that channel. In other cases, the channel may simply need to be cleared from transmissions altogether for other reasons. In such instances, the AP is considered to be in “vacation” mode. When in vacation mode, the AP generally sends a frame which sets a NAV for the duration of the vacation as setting the NAV prevents frames from being sent. One perceived shortcoming with this technique is that the clients are not able to enter a sleep mode as it is unknown how long the AP will remain in vacation mode. As such, the clients must be ready to receive frames at any time. It should be further noted that a 802.11 radio generally consumes as much power when it is in idle mode as when it is actively receiving frames from the AP. Accordingly, various needs exist in the industry to address the aforementioned deficiencies and inadequacies.